The present invention relates to an endoscope having a treatment tool guide section.
A conventional endoscope has a channel for inserting and guiding a treatment tool such as a forceps therethrough. A guide unit for guiding the tool is disposed at the opening of the channel. Referring to FIG. 1, this unit has a raising lever housing 2 in a distal end assembly 1 of the endoscope. A raising lever 3 is pivotal about a shaft 4 in the raising lever housing 2, as shown in FIG. 1. A control wire 5 connected to the raising lever 3 is pulled or pushed to change a raising angle of the raising lever 3. Thus, a treatment tool 6 is arbitrarily oriented at a desired angle.
In the conventional device of this type, the raising lever 3 is pivoted by strongly pulling the control wire 5. The raising lever 3 returns to the lying position by pushing the control wire 3. However, the force applied to the direction to push the control wire 5 is hard to be transmitted, preventing smooth pushing of the control wire 5. Especially, when contamination causes clogging at the shaft 4 or a wire insertion hole 7, the raising level 3 may not return to the lying position. Further, since the raising lever 3 has a predetermined shape and is not flexible, a portion 6a which is sharply bent is formed when a raising angle is increased. The treatment tool 6 is often broken at the portion 6a. The raising lever becomes thick and the distal end portion becomes large in the conventional endoscope.